1. Field of the Invention
The present invention relates generally to the art of producing a water repellent film on various substrates, and more particularly, to improving the durability of water repellent films by activating the substrate with an acid solution prior to applying the film.
2. Relevant Art
U.S. Pat. No. 4,997,684 to Franz et al. discloses a method for providing a durable nonwetting surface on glass by contacting the glass with a perfluoroalkylalkyl silane and a fluorinated olefin compound and heating the glass to produce a durable non-wetting surface.
U.S. Pat. No. 5,328,768 to Goodwin discloses a technique for producing a durable non-wetting surface on a glass substrate wherein the surface of the substrate is treated with a silica primer layer and a perfluoroalkylalkyl silane over the primer layer. The silica primer layer improves the durability of the water repellency of the surface. The glass substrate is cleaned with a water and 50/50 by volume isopropanol/water solution prior to application of the primer.
U.S. Pat. No. 5,523,162 to Franz et al. discloses a method for producing a durable non-wetting surface on a plastic substrate which includes treating the plastic substrate with a silica primer layer and a perfluoroalkylalkyl silane. The plastic substrate was cleaned with hexane then methanol prior to application of the primer.
While the foregoing U.S. patents and pending U.S. application disclose durable water repellent films, it can be appreciated by those skilled in the art that making available additional technology to improve the durability of the water repellent surface is advantageous and desirable.